Low density edible animal chews and methods of making same

Abstract

Edible chews for pets have a low density (e.g. about 1.0 Kg/L or less) and a smooth exterior surface. One method by which the low density and the smooth exterior surface can be achieved uses a modified extrusion die to increase shear and restrict surface bubbles. Another method by which the low density and the smooth exterior surface can be achieved uses an extruder screw with a modified profile that holds a dough longer therein to create a whipping effect resulting in more bubble nucleation sites and hence a more uniform cellular matrix. The puffed (expanded) product was experimentally tested and provided better dental cleaning scores than a current unexpanded similarly formulated commercial dental product.

The invention is claimed as follows: 
     
         1 . A method of making an edible pet chew, the method comprising:
 preparing a dry mix comprising a pre-gelatinized cereal flour;   metering the dry mix into an extruder comprising an extrusion die;   adding a hydrogen bond-forming component to the dry mix to form a dough;   promoting nucleation of the dough by subjecting the dough to a combination of shear and temperature in the extruder; and   directing the nucleated dough through an opening of the extrusion die comprising grooves, each of the grooves has an open end and a bottom surface opposite to the open end, and the width of the bottom surface is greater than the width of the open end.   
     
     
         2 . The method of  claim 1 , wherein the grooves have a substantially triangular cross-section. 
     
     
         3 . The method of  claim 1 , wherein the grooves have a width that continuously decreases as the grooves extend toward the center of the opening. 
     
     
         4 . The method of  claim 1 , wherein the grooves are evenly spaced along an inner periphery of the opening of the extrusion die. 
     
     
         5 . The method of  claim 1 , wherein the temperature applied to the dough is at least 120° C. 
     
     
         6 . The method of  claim 1 , wherein the hydrogen bond-forming component comprises a polyhydric solvent. 
     
     
         7 . The method  claim 1 , wherein the dry mix further comprises a bicarbonate. 
     
     
         8 . The method of  claim 7 , wherein the bicarbonate is sodium bicarbonate. 
     
     
         9 . The method of  claim 8 , wherein the sodium bicarbonate is 0.2 to 1.5 wt. % of the dry mix. 
     
     
         10 . The method of  claim 1 , wherein the extruder further comprises a barrel comprising a vent and a vent-stuffer. 
     
     
         11 . The method of  claim 10 , comprising using a reverse element of the extruder to extend a time spent by the dough in the barrel comprising the vent and the vent-stuffer. 
     
     
         12 . The method of  claim 10 , comprising using mixing elements in the barrel comprising the vent and the vent-stuffer to whip the dough and promote the nucleation of the dough. 
     
     
         13 . The method of  claim 10 , comprising aerating the dough in the barrel comprising the vent and the vent-stuffer. 
     
     
         14 . The method of  claim 10 , comprising using the vent to provide ambient pressure. 
     
     
         15 . The method of  claim 1 , wherein the combination of shear and temperature is applied to the dough in a section of the extruder adjacent to the extrusion die, wherein the temperature in the section adjacent to the extrusion die is higher than a temperature of at least one previous section of the extruder. 
     
     
         16 . The method of  claim 1 , wherein the edible pet chew has a substantially smooth exterior surface and a density not greater than about 1.0 Kg/L. 
     
     
         17 . The method of  claim 16 , wherein the edible pet chew has a caloric density of 1.5-2.7 Kcal/cm 3 . 
     
     
         18 . The method of  claim 16 , wherein the density of the edible pet chew is at most about 0.9 Kg/L. 
     
     
         19 . An edible pet chew made by a process of  claim 1 . 
     
     
         20 . A method of cleaning teeth of a pet, the method comprising administering to the pet an edible pet chew made by the process of  claim 1 , wherein the edible pet chew comprises an expanded pre-gelatinized cereal flour matrix and has a substantially smooth exterior surface and a density not greater than about 1.0 Kg/L.